Electric-current distributer



' (No Model.)

No. 543,198. Patented July 23, 1895.

l 1 l 1 l l l A INVENTU S: 1 Elihu 1700708070 24 W Edwim W. Rica J?flflorw UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF SIVAMPSCOTT, AND EDvVIN 1V. RICE JR, OF LYNN,

MASSACHUSETTS, ASSIGN ORS TO THE THOMSON-HOUSTON ELECTRIC COM- PANY, OFCONNECTICUT.

ELECTRIC-CURRENT DISTRIBUTER.

SPECIFICATION forming part of Letters Patent No. 543,198, dated July 23,1895.

Original application filed April 24, 1884, Serial No. 127,792. Dividedand this application filed October 3,1892. Serial No. 447,604. (Nomodel.)

To aZZ whom it may concern:

Be it known that we, ELIHU THOMSON, residing at Swampscott, and EDWINWV. RICE, Jr., residing at Lynn, in the county of Essex 5 and State ofMassachusetts, citizens of the United States, have invented a certainnew and useful Electric-Current Distributor, of which the following is aspecification.

Our invention relates to electric switches [O or safety devices designedto prevent injury to an apparatus in an electric circuit from abnormalflow of current therein.

Our invention consists, essentially, in holding or retaining the switchor cut-out device in normal position by means of some material which isadapted to fuse or soften by heat, and is placed in such relation to aconductor, subject to overheating under abnormal conditions, as to befused or softened sufficiently to release the switch.

Our invention consists, also, in details of construction andcombinations of devices hereinafter described, and more particularlyspecified in the claims.

2 Our present application forms a division of an application filed by usApril 24:, 1884, Serial No. 127,792.

In the accompanying drawing, we have illustrated one form of apparatusin which 0 the invention may be embodied.

M and L are devices in the electric circuit to be protected. L is anelectric lamp or other translating device, and M represents the wirecoils of an electromagnet. The circuit for 5 these devices is suppliedwith current from the wires a b in any usual or proper manner.

K is a circuit-opening switch designed to operate under abnormalconditions and open the circuit containing L and M.

The operation of the device K might be used to bring other switches intooperation, as will be presently described.

The switch or safety device K, as shown, is a spring normally held incircuit-closing position by means of a drop of solder, which holds itdown so as to complete the circuit of the coil M, the contact beinguponthe coil itselfas, for example, upon its outer layer. spring K has abias, which tends to throw it away from the coil when the solder fusesor softens. Normally, the heat generated in the coil by the passage ofthe current is insufficient to melt the solder and release the switch;but when the coil heats abnormally by current in the circuit to beprotected the jointis melted and the circuit is opened by thespringswitch.

The abnormal heating of the coil or conductor or melting or softening ofthe solder might be used to bring into operation a shunt- 6o ing-switch,which is normallyin circuit-opening position so long as the spring K isheld by the solder. Thus, for instance, if the coils M be the coils ofthe electromagnet to be energized the magnet may be used to operate onan armature N and thereby hold the contact C away from opposite contact,through which, when contact is established, a shunt is formed around thecircuit containing M and L. This shunt may include a resistance R, orsuch resistance might be dispensed with. When the resistance Bisemployed, it is preferably wound upon a tube D, of brass, copper, orother good conductor, preferably open at top and bottom for circulationof air, and 7 is preferably made of German silver, as the resistance ofthis material changes but slightly with the temperature. The tube D actsinductively to prevent spark at the opening of the contact C.

Our invention is adapted for use on an electric circuit carrying such asmall current that the ordinary fuse-wire cannot safely be employed on.account of its weakness and consequent liability to accidental ruptureor 8 breakage.

In our invention the heat generated in the circuit when under abnormalconditions can accumulate and act on the fusible metal or material,which is softened by heat and is placed adjacent to the conductor inwhich the heat is generated, the material so softened or fused servingto control the circuits or connections so as to prevent any damage froman abnormal flow of current. 93

What we claim as our invention is- 1. In an electric circuit, thecombination of an electromagnetic coil subject to overh eating underabnormal conditions, a fusible material arranged to receive heat fromthe said coil when overheated and serving to retain the circuitcontroller in its normal position during normal work in the coil, andmeans for causing the operation of the circuit controller on thesoftening or melting of the fusible material owing to the heataccumulated in the coil.

2. In an electric circuit, the combination, of an electromagnet and anarmature controlled thereby, of a biased circuit breakerin the circuitof the coil of the magnet, and soft solder holding said circuit breakeragainst its bias in electrical contact with the vcoil.

Signed at Lynn, in the county of Essex and State of Massachusetts, this26th day of September, A. D. 1892.

ELIHU THOMSON. EDWIN W. RICE, JR. Witnesses:

J OHN W. GIBBONEY, BENJAMIN B. HULL.

